Spring-fork for cycles, motor-cycles, and the like.



G. F. sHIIvIMIN.

SPRING FORK FOR CYCLES, MOTOR CYCLES, 4AND THE LIKE.

APPLICATION FILED IAN. I2, 1914.

1,166,156.. vPatented Dec. 28, 1915.

2 SHEETS-SHEET l.

coLuMmA PLANOGRMH :0..WASHINOTOIL u. c.

G. F'. SHIMMIN.

SPRING FORK FOR CYCLES, MOTOR CYCLES, AND THE LIKE.

APPLICATION FILED JAN. 12, 1914.

1,166,156. Eatented Dee. 28,1915.

I 2 SHEETS-SHEET 2.

CDLUMBIA PLANouRAPn co..wAsHxNGTON, D. c.

GEORGE FEATHERSTONE SHIMMIN,

OF MARYPORT, ENGLAND.

SPRING-'FGRK FR CYCLES, MOTOR-CYCLES, AND THE LIKE.

Specification of Letters Patent.

Patented Dec. 28, i915.

Application led January 12, 1914. Serial No. 811,635.

To all whom t may concern.'

Be it known that l, GEORGE FnATr-rnns'ronn Summum a subject of the King of the TUnited kingdom of Great Britain and lreland, and resident of Maryport, England, have invented a certain new and useful linprovement in Spring-Forks for Cycles,

Motor-Cycles, and the like, of which the following is a specification.

rlhis invention relates to improvements in spring forks for cycles, motor-cycles and the like, and has for its objectto provide a construction of spring forks in which is combined with the usual rigid forks a system of linked levers or toggles and main and rebound springs.

ln the accompanying drawings illustrating the invention, Figure l is a side elevation of one form of the improved spring fork; lfigs. 2 and 3 are respectively a front elevation and a side elevation partly in section of a slightly modified construction; and Fig. Ll is a plan, partly in section, showing an alternative arrangement.

ln accordance with the invention, and as represented in the accompanying drawings illustrating the improved spring forks as applied to a motor-cycle, the said forks comprise in combination with the usual curved rigid forks A of the machine frame as shown at l? ig. 3, or with fork bars A. bolted to the usual stein tube lil as shown at Fig. l, short levers B pivoted at the lower ends of thes forks and supporting the front wheel axle. Through said levers B pressure due to the weight of the fore-part of the machine is transmitted to two pairs of compression rods or toggles C, D, one pair C of which is connected to the levers B while each member of the other pair D is hingedly connected at its upper end to the stemtnbe or stem-tube fitting E2 of the rigid fork A as indicated at 3 or to the upper end E of an upward extension of the fork bars A. as indicated at Fig. 1. The point of connection at f of each pair of compression rods C. D. is movable relatively to the stem-tube and 1s resiliently connected thereto by means of a rod l pro- 4vided with combined main and rebound and is held by nuts bearing on a cap K on the outer end of the tubular guide g. The spring G is held normally in compression between a flange at one end of the guide 7 bearing on the swiveling crosshead H, and the flanged end of a block L on which the guide g is free to slide; while the spring G is held between a flange engaging the swiveling crosshead H and a flange on the outer end of the tubular guide g so that it is held normally under compression.

'ln an alternative arrangement as shown in Fig. l there is substituted for the spring Gr a pair of tension springs U. arranged One on each side of the spring Gr, each attached at one end to the bracket M secured to said rigid fork A or A and at the other to the swiveling crosshead H connecting the rods C. D. or as shown, to the ends of a. rocker Npivoted at Q on a bracket R connected to or formed integral with said crosshead H, so as to maintain equal pressure on each spring 0 rl`he short levers B above referred to may be arranged to project either rearwardly or forwardly of the ordinary rigid forks A or A as shown in Figs. l and 3. In the latter case, the device can be more easily applied to slightly curved, or straight forks, as fitted to some makes of motor-cycles and the like. The improved spring fork arrangement is also applicable to some makes of cycle car.

Having now described my invention, l declare that what l claim and desire to secure by liettersljatent of the United States is l.. ln a spring fork device for the front wheel of a cycle, in combination with a rigid bifnrcated member, downwardly extending rods each having an articulated connection with the upper end of said bifnrcated member, two levers one pivotally connected to the lower end of each tine of said bifurcated member, saidy levers formed for attachment to the wheel spindle, a pair of upwardly extending rods one pivotally conh nected at its lower end to each of said levers and at its upper end with the lower eX- remity of cach of said downwardly eX- tending rods, the connection of said sets of rods affording a toggle joint, and a main and rebound spring means connecting said connection and said bifurcated member.

ln a spring fork device for the front wheel of a cycle, in combination with a rigid bifurcated member, downwardly eX- tending rods reach having an articulated connection with the upper end of said bifurcated member, two levers one pivotally connected to the lower end of each tine of said bifurcated member, said levers formed for attachment to the wheel spindle, a pair of upwardly extending rods one pivotally connected at its lower end to each of said levers and at its upper end with the lower extremity of each of said downwardly extending rods, the connection of said sets of rods a'tl'ording a toggle joint, a spring intel'- posed between said joint and said bifurcated member, a crosshead, a bracket on said erosshead, a lever pivoted centrally to said bracket, and springs interposed between the ends of said last mentioned lever and said biurcated member.

3. ln a spring fork device for the front wheelof a cycle, the combination, with a rigid bifurcated member, of two levers one pivotally connected to the lower end of each tine of the bifurcated member, said levers formed ttor attachment te the wheel'spindle; a pair of downwardly extending rods pivotally connected, for angular movement, at their upper ends to the upper part 01' the bifurcated member; a pair of upwardly extended rods pivotally connected respectively, at their lower ends, with said levers,

and at their upper ends with the lower ends of said downwardly extending rods, whereby a toggle joint is formed; and a spring connecting said joint and said member.

4. In a spring fork device for the front wheel of a cycle, the combination, with a rigid bifureated member, of two levers one pivotally connected to the lower end oi each tine of the bifurcated member, said levers formed for attachment to the wheel spin dle; a pair of downwardly extending rods pivotally connected, for angular movement, at their upper ends to the upper part of the bifureated member; a pair of upwardly ex tending rods pivotally connected respectivel at their lower ends with said leA g vers, and at their upper ends with the lower ends of said downwardly extending rods, whereby a toggle joint is formed; and a main and rebound spring connecting said joint and member.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE FEATHERSTONE SHIMMIN.

`Witnesses:

JOSEPH WATTS Moivnnonsn, THOMAS Dom.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington. D. C.

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